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IXXX10.1177/1071100712464354Foot & Ankle InternationalAl-Abbad and Simon 2013
FA
The Effectiveness of Extracorporeal Shock Wave Therapy on Chronic Achilles Tendinopathy: A Systematic Review
Foot & Ankle International 34(1) 33–41 © The Author(s) 2013 Reprints and permission: sagepub.com/journalsPermissions.nav DOI: 10.1177/1071100712464354 http://fai.sagepub.com
Hani Al-Abbad, PT, BSc, MMSPhty1, and Joel Varghese Simon, PT, MMSPhty2 Abstract Background: Achilles tendinopathy is a pathological state resulting from repetitive loading or stress on the tendon. Extracorporeal shock wave therapy (ESWT) is hypothesized to be an effective alternative intervention to surgery when other conservative therapies fail. This systematic review investigated the effectiveness of ESWT in the treatment of insertional and noninsertional Achilles tendinopathies. Methods: Articles were electronically searched from the Cochrane Controlled Trials Register, MEDLINE, CINAHL, EMBASE, and SPORTDiscus using a comprehensive search strategy. Studies were included if they were prospective clinical trials examining the effectiveness of ESWT for insertional or noninsertional Achilles tendinopathies. Methodological quality of included studies was assessed using PEDro scale and Modified McMaster tool.The strength of the evidence was reported using the National Health and Medical Research Council body of evidence framework. A narrative summary of the findings was presented. Results: Four of the included studies were randomized controlled trials, and 2 were pre-post study designs. Common methodological deficiencies included not blinding the clinician and participants. There was consistent evidence from 4 reviewed studies on the effectiveness of ESWT in the management of patients with chronic Achilles tendinopathies at a minimum 3 months’ follow-up. Conclusion: Overall, our review showed satisfactory evidence for the effectiveness of low-energy ESWT in the treatment of chronic insertional and noninsertional Achilles tendinopathies at a minimum 3 months’ follow-up before considering surgery if other conservative management fails. However, combining ESWT with eccentric loading appears to show superior results. Level of Evidence: Level 1, systematic meta-analysis. Keywords: Achilles, chronic, extracorporeal, shock wave, tendinopathy
Achilles tendinopathy is one of the most frequently encountered overuse injuries, especially in the athletic population,3 accounting for 5% to 18% of all running injuries. Tendinopathy was described by Cook and Purdam5 as a pathological state of the tendon that results from repetitive loading or stress shielding that may lead to a catabolic effect on tendon integrity. There are 3 stages to tendon pathology: early reactive, disrepair, and degenerative. The management for tendinopathies depends on the stage of pathology and should consider factors such as age, repetitive loading, and the presence of bony spurs.5 Achilles tendinopathy may involve lesions in the tendoachilles, the enthesis organ, the surrounding peritendinous structure, or a combination of these structures.24 The impairments associated with this condition include loss of muscle power, pain, and stiffness of surrounding soft tissues. As a result, patients with this condition often experience limitations in their ability to walk, run, climb, and perform household activities and sports.3 In recent years, there has been substantial investigation to understand tendon pathophysiology, which has led to a
change in management strategies for Achilles tendinopathies. The management of chronic Achilles tendinopathies has shifted from passive inflammation management only to active exercises and pharmacological interventions.1 Extracorporeal shock wave therapy (ESWT) is a recent addition to the list of management choices and has shown promising outcomes such as a decrease in pain and an improvement in functional scores in managing chronic tendinopathies.5 A number of systematic reviews have been published in the past 10 years reporting the effectiveness of different management approaches to Achilles tendinopathy. In 2001, McLauchlan and Handoll13 reviewed clinical trials that
1
King Fahad Medical City, Riyadh, Saudi Arabia Strathalbyn Physiotherapy, Strathalbyn, South Australia
2
Corresponding Author: Hani Al-Abbad, PT, BSc, MMSPhty, King Fahad Medical City, PO Box 59046, Postal Code 11525, Riyadh, Saudi Arabia Email:
[email protected]
34 investigated the effectiveness of various treatment interventions for acute and chronic Achilles tendinitis. This review found insufficient evidence to determine which method of treatment is most appropriate for Achilles tendinitis. A recent review on insertional Achilles tendinopathy management9 reviewed both surgical and conservative approaches for treating the condition. This review aimed to include only prospective trials, but it also included 1 retrospective cohort study to review ESWT. A review by Magnussen et al12 evaluated the effects of nonsurgical interventions, including ESWT, for noninsertional Achilles tendinopathies. Their review included 2 trials on ESWT, one of which included a mixed population of tendons and could have been excluded according to their mentioned criteria.6 A guideline published by Carcia et al3 addressed Achilles tendinopathy with a wider scope to suggest examination choices and treatment recommendations but included only 2 studies on ESWT. Since there are no high-quality reviews on this topic and methodological issues in the ones available in literature, there is need for a systematic review focusing on the effect of ESWT on both insertional and noninsertional chronic Achilles tendinopathies. This review aimed to explore the effectiveness of ESWT in the treatment of chronic insertional and noninsertional Achilles tendinopathy
Methods Search Strategy As a first step in the systematic review process, we framed our review question using the PICOT (population, intervention/ exposure, comparison, outcome, time frame) framework (Table 1). A range of keywords was identified and grouped into 2 categories to ensure that a broad search would be conducted. Category 1 represented key words within the concept of “Achilles tendinitis” (OR “Achilles tendinopathy”). Category 2 represented key words within the concept of “shock wave therapy” (“extracorporeal shock wave therapy” OR “ESWT”). Wildcards and truncations symbols were used as appropriate across different databases. We conducted a comprehensive search using the following electronic databases: MEDLINE, EMBASE, SPORTDiscus, CINAHL, and the Cochrane Controlled Trials Register. Reference lists of all relevant articles were examined for additional studies that may not have been indexed in the electronic databases.
Study Selection We considered all experimental designs in this review because of a limited number of studies with high methodological quality. Our review examined studies that investigated the effects of ESWT on insertional and/or noninsertional Achilles tendinopathy. Only articles published in English within the past 10 years were included.
Foot & Ankle International 34(1) Table 1. The PICOT Format Population
Male or female adults aged 18 years or older with chronic Achilles tendinopathy (both insertional or noninsertional)a Intervention/exposure Extracorporeal shock wave therapy Comparison Any conservative treatment or sham Outcome Pain Foot/ankle or lower extremity function score Time frame Short term and long term (postintervention follow-up for 3 months or longer) Abbreviation: PICOT, population, intervention/exposure, comparison, outcome, time frame. a Chronic is defined as a condition lasting for more than 3 months. Achilles tendinopathy is defined as an overuse tendon injury and can be classified according to the location of the pathology into insertional, which is close to the calcaneus, and noninsertional (also called midportional), which is found 2 to 6 cm proximal to the calcaneus.
Two reviewers independently (H.A. and J.V.S.) scrutinized the titles and the abstracts to determine eligibility for inclusion. Full texts of potentially relevant papers were retrieved for a more detailed examination. The decision to include or exclude studies, based on the set criteria, was made independently by the same authors. Differences in opinions were resolved by discussion until a consensus was reached.
Methodological Quality Assessment The methodological quality of all included studies was independently assessed by 2 authors (H.A. and J.V.S.). The PEDro scale, which is scored out of 10, was used to examine the quality of the randomized controlled trials (RCTs). It is an assessment scale of the methodological quality and risk of bias of clinical trials.17 Non-RCTs were assessed using the Modified McMaster Quantitative Critical Appraisal Tool.7 This tool yields a maximum score of 15. It contains a generic quantitative appraisal scale. Differences in scoring between reviewers were resolved by discussion until a consensus was reached.
Data Extraction and Synthesis The first author (H.A.) extracted data from individual studies and included characteristics of the population studied, description of the intervention, outcomes assessed, and results of individual studies. All extracted data were double-checked by the second author (J.V.S.) for rigor. This extracted data were compiled into a tabular form (Table 2). Data were synthesized using a qualitative/narrative approach. Synthesis of collected data was then collectively reviewed. This step included comparing the studies and then discussing the quality of evidence, clinical impact, consistency of findings, generalizability of the results, and the recommendations based on the National Health and
35
48.5 (35-77)
Lakshmanan 2004 Shock wave 16a therapy and O’Doherty10
No. of tendons.
a
58.7 ± 10.8
2005 Shock wave 22 therapy
Costa et al6
49 ± 9 51.2 ± 10.3
2008 Shock wave 24 therapy
Rompe et al21 2007 Shock wave 25 therapy
Rasmussen et al18
40.4 ± 11.3
N
Rompe et al20 2008 Shock wave 25 therapy
Group 47.8 ± 12.8
Year
Vulpiani et al23 2009 Shock wave 127a therapy
Author
>6
17.8 ± 10.1
12.5 ± 6.8
>3
26.3 ± 10.7
>6
Interval Between Sessions
Other Interventions
2000 impulses, 0.12-0.51 mJ/ mm2, 50 Hz
3
3
3
4
1 wk
1 mo
1 wk
1 wk
None
None
Stretching and eccentric loading training None
4 (range, Average 2 d (range, None 1500-2500 impulses, 3-5) 2-7) 0.08-0.33 mJ/mm2 for midportion; 1500-2500 impulses, 0.12-0.40 mJ/ mm2 for insertional calcific tendinopathy 3 1 wk 2000 impulses, 0.12 mJ/mm2
Area of maximal 2000 impulses, 0.1 mJ/mm2 tenderness in a circumferential pattern, starting at the point of maximum pain level Treatment area was 1500 impulses, 0.2 mJ/mm2 identified using patient’s tenderness and ultrasound as a guide Painful area in the Achilles 2000 impulses, 6-10 Hz tendon with constant motion of probe around the lesion under 2.5 bar pressure in a continuous mode pattern
Using ultrasonography guidance to focus the shock waves on insertional or midportion tendinopathy or calcified area Area of maximal tenderness was treated in a circumferential pattern, starting at the point of maximum pain Delivered to the area of swelling and tenderness
Duration of Age, y, Mean ± Symptoms, mo, No. of Impulses and Dosage No. of SD or (Range) Mean ± SD Shock Wave Application (Energy Flux Density) Sessions
Table 2. Characteristics of Studies and Intervention Details
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Figure 1. CONSORT diagram.
Medical Research Council (NHMRC)14 strength of the body of evidence matrix.
Results Search Results An overview of the search results is outlined in Figure 1. The selection of studies was based on the PRISMA
(Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines. Of the initial 83 titles identified from the databases, 48 were excluded as they did not satisfy the inclusion criteria, leaving 35 studies for possible inclusion in the review. Upon examination, 26 were duplicates and 2 were nonexperimental studies. One article was excluded as contamination of data occurred with combined interventions. Therefore, studies included in the review comprised 4 RCTs and 2 pre-post studies.
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Al-Abbad and Simon
Participants’ Characteristics
Effects of ESWT on Achilles Tendinopathy
The number of participants for each study varied from 16 to 127, and a total of 365 tendons were available for analysis. Table 2 provides a summary of the participants’ characteristics. Of the 6 studies reviewed, 2 dealt exclusively with noninsertional Achilles tendinopathy,10,21 1 on insertional tendinopathy,20 and 2 articles included both types of tendinopathies.6,23 The study by Rasmussen et al18 did not specify the type of tendinopathy in their inclusion criteria. The age of participants ranged between 35 and 69.5 years. The duration of symptoms varied widely across studies, ranging between 3 and 42 months. Overall, there was lack of consistency in the characteristics of participants across studies.
Pain. Of the 6 studies, 410,20,21,23 reported statistically sig-
Treatment Parameters Table 3 outlines the treatment parameters used by individual studies. The majority of the studies described the application of ESWT at the area of maximal tenderness or swelling.10,18,20,21 Two others6,23 used ultrasound guidance to focus shock waves on tendinopathy or calcified areas. The dosage of ESWT differed among studies, with energy levels ranging between 0.08 and 0.51 mJ/mm2 (reported in energy flux density) and impulses per session varying between 1500 and 2500 impulses. In all studies, the number of treatment sessions was either 3 or 4, except for 1 study23 that reported a variable number of sessions. The time interval between treatments was 1 week in most studies,10,18,20,21 whereas Costa et al6 used a 1-month interval, and Vulpiani et al23 reported intervals between 2 and 7 days. Most studies examined ESWT as a single intervention.6,10,21,23 Two studies had cointerventions; 1 study allowed the use of analgesics as necessary,20 whereas another administered stretching and an eccentric loading training program to all participants.18
Outcome Measures Pain outcomes were expressed using either a visual analog scale (VAS)6,10,18,23 or the Numerical Rating Scale (NRS).20,21 All studies reported pain outcomes after 3 to 4 months of follow-up, wherein 2 had a longer term followup of 12 to 24 months.10,23 The VISA-A (Victorian Institute of Sport Assessment–Achilles) was used to evaluate function in 3 studies.10,20,21 Other measures of function were reported by other studies such as the Disability Rating Index/Functional Index for Lower Limb Injuries (FIL),6 the American Orthopaedic Foot and Ankle Society (AOFAS) score,18 and the Ankle Hindfoot Scale (AHS).10 All outcome measures used have been tested for validity and reliability and have shown good responsiveness to change.
nificant improvements in pain scores (VAS or NRS) at a minimum of 4 months despite the variability in ESWT application parameters between these studies. The study by Rasmussen et al18 showed no difference in the change of pain measure between ESWT and control. Costa et al6 reported no significant difference between groups on VAS score during walking or rest at the 3-month follow-up. However, pain scores during sports activity showed improvement with 13 of 41 tendons becoming pain free at the 1-year follow-up. Function. Functional outcomes were assessed in 5 studies, and 4 showed statistically significant improvement.10,20,21,23 Costa et al6 reported no change in the FIL measure. All outcome measures for function were measured at a minimum period of 3 months from baseline.
Methodological Quality The quality of the included studies is summarized in Tables 4 and 5. Four studies were RCTs, and 2 were pre-post design. Scores of RCTs on the PEDro scale ranged between 7-9 and 10. All studies reported random allocation of participants, similar groups at baseline, assessor blinding, adequate follow-up, and intention-to-treat analysis. Concealed allocation was undertaken by all studies, except for one.18 None of the studies had therapist blinding, and only 2 reported participant blinding.6,18 All studies reported between-group statistical analysis using both point measures and measures of variability except for one.18 The 2 pre-post studies were appraised using the Modified McMaster Quantitative Critical Appraisal Tool. These studies obtained a score of 9 out of 14 and 11 out of 14, respectively. Both reported adequately on details of intervention, dropouts, and clinical importance. There was clear reporting of study purpose and sample characteristics, with appropriate conclusions. Results of both studies were reported in terms of statistical significance. However, neither provided adequate background literature review nor justified the sample size. Only 1 study used valid and reliable outcome measures and appropriate statistical methods.10 Cointervention was avoided in only 1 study.23
Overall Appraisal of Evidence Summary of the strength of evidence is provided in Table 6. There is an overall satisfactory level of evidence for the effectiveness of ESWT for the treatment of chronic Achilles tendinopathies on pain and function. Despite inconsistencies in the inclusion criteria, type of tendinopathy, and area of application, 4 of 6 studies showed significant positive outcomes except for Costa et al6 and Rasmussen et al.18
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Table 3. Outcome Measures Follow-up Author,Year
SWT Group
Vulpiani et al, 200923 Rompe et al, 200820
SWT
Rasmussen et al, 200818 Rompe et al, 200721
SWT
Costa et al, 20056 Lakshmanan and Doherty, 200410
SWT
SWT
SWT
SWT
Within Group
Between Group
2.88 ± 3.1 2.6 ± 3.3 79.4 ± 10.4 (34-100) 2.8 ± 1.6 (1-6) 3.0 ± 2.3 (0-8) 3.5 ± 1.1 (1.5-5.2) 2.4 ± 4.2 (1-7)
